חומר רקע
Citation: Beretta, A.; Manuelli, M.;
Cena, H. Favism: Clinical Features at
Different Ages. Nutrients 2023, 15,
343. https://doi.org/10.3390/
nu15020343
Academic Editors: George
Briassoulis, Panagiotis Briassoulis
and Stavroula Ilia
Received: 6 December 2022
Revised: 28 December 2022
Accepted: 5 January 2023
Published: 10 January 2023
Copyright:
© 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed
under
the
terms
and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
nutrients
Review
Favism: Clinical Features at Different Ages
Alice Beretta 1,*
, Matteo Manuelli 2 and Hellas Cena 1,2
1
Laboratory of Dietetics and Clinical Nutrition, Department of Public Health, Experimental and Forensic
Medicine, University of Pavia, Via Bassi 21, 27100 Pavia, Italy
2
Clinical Nutrition and Dietetics Service, Unit of Internal Medicine and Endocrinology, Istituti Clinici
Scientifici Maugeri IRCCS, 27100 Pavia, Italy
*
Correspondence: [email protected]
Abstract: Favism is a hemolytic disease due to the ingestion of fava beans in individuals with
glucose-6-phosphate dehydrogenase (G6PD) deficiency. There is wide inter- and intra-individual
variability in the development of hemolytic crisis, and several factors influence it: quantity, quality,
ripeness of fava beans, and age of onset. In this narrative review of case reports and case series,
we reported the predisposing factors and clinical features for four different age groups classified as
follows: pregnant women and infants (i.e., exclusively breastfed children); children, from weaned to
11 years; preadolescents and adolescents, from 11 to 18 years; and adults (18 years and older). Some
symptoms developed only in specific age groups: death in infants; visual impairment in children;
systolic murmur in infants, children, and adolescents; and renal failure in adults. In youngest children
or pregnant women the severity is the highest. Some other symptoms were present in all: jaundice,
increased bilirubin, splenomegaly, hepatomegaly, discolored urine, tachycardia, pallor, abdominal
pain, malaise, vomit, nausea, and dizziness. Laboratory findings are characterized by anemia,
reticulocytosis, elevated bilirubin level, and sometimes urinary urobilinogen and methemoglobinemia.
In most cases the symptomatology is self-limited and does not release sequelae, but hospitalization
and transfusion are often required.
Keywords: favism; G6PD deficiency; nutrition; hemolysis
1. Introduction
Favism is a hemolytic disease due to the ingestion of fava beans in subjects with
glucose-6-phosphate dehydrogenase (G6PD) deficiency. This is a common erythrocyte
enzyme deficiency with sex-linked inheritance caused by the presence of a mutation in
the constitutive Gd gene. G6PD participates in pentose phosphate metabolism, and it is
responsible for maintaining an adequate reducing potential in the erythrocyte. Enzymatic
variants, resulting from mutations in the polymorphic gene, have different levels of activity
which result in different manifestations of the defect at the clinical level. Based on biochem-
ical and clinical characteristics, the WHO [1] has classified G6PD variants into four classes
as shown in Table 1.
Table 1. WHO classification of G6PD variants.
Class
Median of G6PD Activity
Hemolysis
A
<20%
Chronic
B
<45%
Acute, triggered
C
60–150%
No hemolysis
U
Any
Uncertain clinical significance
At steady state, most of the deficit carriers do not show clinical manifestations; the
enzymatic defect corresponds to a mild hemolytic state that, in most cases, is perfectly
compensated [2]. When an exogenous trigger induces increased oxidative stress in red
Nutrients 2023, 15, 343. https://doi.org/10.3390/nu15020343
https://www.mdpi.com/journal/nutrients
Nutrients 2023, 15, 343
2 of 19
blood cells, a hemolytic crisis occurs. In the case of favism, the triggers are two components
present in fava beans: vicine and convicine. In the intestine, the two beta-glucosides are
converted into their respective aglycones, divicine and isouramil. Their action is to increase
the production of free radicals that eventually lead to the oxidation of glutathione. The
deficiency of G6PD results in a deficiency of NADPH, whose major task is to reduce the
oxidized glutathione, especially in red blood cells, which is a strong oxidizing agent and
as such can lead to the onset of a hemolytic crisis. The presence of these glucosides is the
discriminating factor between broad beans and other legumes; in fact, other legumes do
not present the triggering agents [3]. The quantity of vicine and convicine determine the
onset or not of the hemolytic crisis and, in the case of crisis, of its severity also [4].
Hemolytic crises are erratic, so not only are there a wide range of interindividual
severities of the reaction, but only 25% of deficient adults manifest a hemolytic crisis
following fava bean ingestion; even in the same person there is wide variability in the
exacerbation of symptomatology [5]. As reported by Luzzatto and Poggi [6], several factors
influence whether or not a hemolytic crisis occurs: the amount of fava beans ingested,
especially in relation to mass; the quality of the fava beans (i.e., raw, boiled, or canned);
and the degree of ripeness, which corresponds to the amount of glucosides present in the
legume. Finally, age of onset can influence the clinical presentation. Hereafter, we review
studies reporting favism with different ages of onset (see also Table 2).
Nutrients 2023, 15, 343
3 of 19
Table 2. Clinical features of favism in different age groups.
Age
(Years Old)
Gen-
der
Triggering
Foods
Timing
(n. Days)
Previous
Episodes
First In-
gestion
Family
History
Ethnic-
ity
Signs & Symptoms
Vital Parameters
Hb
(g/dL)
Erythrocytes
(x mm3)
Ht
(%)
Reticulocytes
(%)
Serum
Bilirubin
(mg/dL)
Urinary
Urobilino-
gen
Coombs
Test
Transfusion
G6PD Test
Clinical features of favism in pregnant women and infants
Cahill KM
and
Lay AB [7]
35
(pregnant)
F
Fresh fava
beans
1–2
No
No
Yes
Greek
Dark urine
Hepatomegaly
Jaundice
Malaise
Splenomegaly
Systolic murmur
NR
6.0
3,000,000
20
7.6
Total:
3.8
Indirect:
2.9
Positive
Negative
No
Yes
(8.9 U/g Hb)
Mentzer
WC and
Collier E [8]
Newborn
M
Fried and
then dried
fava beans
Last month
of
pregnancy
No
NR
NR
NR
Death
NR
9.8
NR
29
NR
NR
NR
Negative
NR
Yes
Corchia C
et al [9]
2 h old
F
Cooked
dried fava
beans
5
No
NR
NR
NR
Hepatomegaly Pallor
Splenomegaly
Systolic murmur
BP: 52 mmHg
7.3
1,900,000
23
9
10.2
NR
Negative
Yes
(whole blood)
Yes
(4.61 U/g Hb)
Casper J
and
Shulman J
[10]
6 months
old
M
Fava beans
2
No
Don’t
know
No
Yemenite
Death
NR
5.4
1,500,000
NR
65
NR
NR
NR
Yes
(whole blood)
NR
Emanuel B
and
Schoenfeld
A [11]
4 months
old
F
Fava beans
1
No
No
No
Egyptian
Dark urine
Hepatomegaly
Jaundice
Malaise
Pallor
Splenomegaly
BT: 36.8 ◦C
HR: 180 bpm
RR: 60/min
5.7
1,800,000
NR
8.8
Direct:
0.9
Indirect:
3.4
Positive
Negative
Yes
(whole blood)
Yes
Taj-Eldin S
[12]
4 months
old
M
Boiled
dried fava
beans
4
No
NR
NR
Arabic
Dark urine
Hepatomegaly
Jaundice
Malaise Pallor
BT: 37.2 ◦C
HR: 160 bpm
RR: 50/min
3.8
1,480,000
NR
7
Total:
4.2
Indirect:
3.6
Positive
NR
Yes
(whole blood)
Yes
2 months
old
M
Fava beans
5
No
NR
NR
Arabic
Dark urine
Hepatomegaly
Jaundice Pallor
NR
4.7
2,100,000
NR
6
Total:
3.8
Positive
NR
NR
Yes
4 months
old
M
Fava beans
5
No
NR
NR
Arabic
Dark urine
Jaundice
Pallor
Splenomegaly
NR
5.2
1,900,000
NR
12
Total:
4.5
Indirect:
3.2
Positive
NR
NR
Yes
3 months
old
M
Fava beans
4
No
NR
NR
Arabic
Dark urine
Hepatomegaly
Jaundice Pallor
NR
4.0
1,210,000
NR
10
Total:
5.0
Indirect:
3.5
Positive
NR
NR
Yes
Clinical features of favism in children
Wharton HJ
and Dues-
selman W
[13]
3.5
M
Fava beans
0
NR
NR
No
Italian
Anemia
Dark urine
Hepatomegaly
Jaundice
Malaise
Pallor
BT: 102 ◦F
HR: 160 bpm
RR: 30/min
4.2
1,140,000
NR
4.2
NR
Positive
NR
Yes
(whole blood)
NR
Rosen AP
and
Scanlan JJ
[14]
5
M
Fava beans
1
Yes
No
NR
Italian
Abdominal pain
Dark urine
Jaundice
Pallor
Splenomegaly
Systolic murmur
Vomit
BT: 101.6 ◦F BP:
98/68 mmHg
HR: 30 bpm
5.5
1,520,000
35
3.8
NR
NR
NR
Yes
(whole blood)
NR
Nutrients 2023, 15, 343
4 of 19
Table 2. Cont.
Age
(Years Old)
Gen-
der
Triggering
Foods
Timing
(n. Days)
Previous
Episodes
First In-
gestion
Family
History
Ethnic-
ity
Signs & Symptoms
Vital Parameters
Hb
(g/dL)
Erythrocytes
(x mm3)
Ht
(%)
Reticulocytes
(%)
Serum
Bilirubin
(mg/dL)
Urinary
Urobilino-
gen
Coombs
Test
Transfusion
G6PD Test
Pickering
DE
and
Hurwitz S
[15]
28 month
old
M
Fava beans
1–2
NR
No
NR
Italian
Dark urine
Jaundice
Malaise
Systolic murmur
NR
5.75
2,500,000
18
NR
NR
Positive
Negative
Yes
(whole blood)
NR
Larkin VD
[16]
1
F
Fava beans
NR
NR
NR
NR
Italian
Pallor
NR
6.8
3,460,000
NR
NR
NR
NR
NR
No
NR
Tolmas HC
[17]
2.5
M
Fava beans
2
NR
NR
Yes
Italian
Dark urine
Hepatomegaly
Jaundice
Pallor
Splenomegaly
Systolic murmur
BT: 101 ◦F BP:
100/70 mmHg
HR: 140 bpm
5.4
1,910,000
17
8.8
Direct:
0.3
Indirect:
2.6
NR
Negative
Yes
(whole blood)
NR
Diggle JH
[18]
3.5
M
Fava beans
NR
NR
No
NR
Cypriot
Abdominal pain
Anemia
Dark urine
Jaundice
Pallor
Systolic murmur
NR
4.35
NR
NR
NR
NR
NR
Negative
Yes
(whole blood)
NR
9.5
M
Fava beans
0
NR
NR
NR
Cypriot
Anemia
Jaundice
Malaise
NR
9.9
2,320,000
NR
8
6.8
Negative
Negative
No
NR
McCarthy
OR [19]
9
M
Cooked
home-
grown fava
beans
2
No
NR
Yes
NR
Hepatomegaly
Jaundice
Malaise
Vomit
NR
NR
3,400,000
NR
24
0.3
NR
Negative
NR
NR
Brooks EA
et al. [20]
3
F
Raw fava
beans
0-2
Yes
No
NR
NR
Abdominal pain
Dark urine
Jaundice
Pallor
Vomit
NR
3
850,000
NR
8
3
Positive
Negative
Yes
(whole blood)
NR
3.5
Raw fava
beans
2
Yes
No
Abdominal pain
Dark urine Jaundice
NR
7.5
2,500,000
NR
1
4.5
Positive
Negative
No
NR
Gower ND
and
Frommer E
[21]
3
M
Fava beans
NR
No
Yes
NR
Cypriot
Dark urine
Malaise
Jaundice
Pallor
Vomit
BT: 100 ◦F
HR: 132 bpm
RR: 28/min
3.6
NR
NR
NR
4
NR
Negative
Yes
(whole blood)
Yes
4
Frozen fava
beans
1
Yes
No
NR
Dark urine
Sore throat
NR
NR
NR
NR
NR
NR
NR
NR
No
Yes
Discombe
G and
Mestitz W
[22]
2.5
F
Fava beans
0-2
NR
NR
No
Middle-
eastern
Malaise
NR
4.4
1,500,000
NR
NR
NR
Positive
NR
Yes
(packed RBC)
NR
Nutrients 2023, 15, 343
5 of 19
Table 2. Cont.
Age
(Years Old)
Gen-
der
Triggering
Foods
Timing
(n. Days)
Previous
Episodes
First In-
gestion
Family
History
Ethnic-
ity
Signs & Symptoms
Vital Parameters
Hb
(g/dL)
Erythrocytes
(x mm3)
Ht
(%)
Reticulocytes
(%)
Serum
Bilirubin
(mg/dL)
Urinary
Urobilino-
gen
Coombs
Test
Transfusion
G6PD Test
Choremis C
et al. [23]
3
M
Fava beans
1
NR
NR
NR
NR
Blindness
Coma
Dark urine
Hepatomegaly
Jaundice
Malaise
Splenomegaly Vomit
NR
6
2,300,000
NR
NR
Total:
5.8
Indirect:
2.0
NR
NR
Yes
(whole blood)
NR
6
M
Fava beans
NR
NR
NR
NR
NR
Partial loss of sight
NR
NR
NR
NR
NR
NR
NR
NR
No
NR
Stewart AG
et al. [24]
4
M
Freshly
harvested
fava beans
1
Yes
No
NR
Norwegian
Ukrainian
Abdominal pain
Dark urine
Jaundice
Pallor
Semicoma
Vomit
NR
6.1
NR
16
9
Total:
6.9
Direct:
0.9
NR
Negative
Yes
(whole blood)
Yes
(0 U/g Hb)
Wong WY
et al. [25]
2.5
M
Yewdow
nuts
NR
NR
NR
NR
NR
Dark urine
Jaundice
Pallor
Systolic murmur
BP: 107/47 mmHg
HR: 104 bpm
RR: 40/min
4.1
NR
11
6.8
Total:
6.6
Direct:
0.3
NR
Negative
Yes
(packed RBC)
Yes
(0 U/g Hb)
Galiano S
et al. [26]
19 months
old
M
Fava beans
3
NR
NR
NR
NR
Dark urine Malaise
NR
5.0
NR
NR
7
NR
NR
Negative
NR
Yes
4
M
Fresh fava
beans
2-3
NR
NR
NR
NR
Anemia
Dark urine Vomit
NR
5.1
NR
NR
9
NR
NR
NR
NR
Yes
6 months
old
F
Fresh fava
beans
1
NR
NR
NR
English-
Jamaican
NR
NR
6.6
NR
NR
5
NR
NR
Negative
NR
Yes
Odièvre
MH et al.
[27]
6
M
Fava beans
1
NR
NR
Yes
Algerian
Dark urine
Lips cyanosis
Pallor
Vomit
Sat02: 80%
9.2
NR
NR
NR
NR
NR
NR
Yes
(packed RBCs)
Yes
(6 U/g Hb)
Leunbach
TL et al.
[28]
4
M
Fava beans
2
NR
NR
NR
Iraqi
Anemia
Cyanosis
Jaundice
Malaise
Sat02: 74%
9.0
NR
NR
NR
4.33
NR
NR
Yes
(packed RBCs)
Yes
(0.08 kU/mol)
6
M
Fava beans
1
NR
NR
NR
Iraqi
Anemia
Sat02: 78%
6.77
NR
NR
NR
6.55
NR
NR
Yes
(packed RBCs)
Yes
(<0.10 kU/mol)
Mohamed
M and
Els I [29]
15 months
old
M
Fava bean
soup
1
No
NR
No
Chinese
Jaundice Pallor
NR
5.0
NR
NR
NR
NR
NR
NR
NR
Yes
(3.2 U/g Hb)
Verdugo L
P et al. [30]
2.7
M
Fresh fava
beans
2
Yes
NR
NR
NR
Abdominal pain
Anemia
Hepatomegaly
Jaundice
Pallor
Vomit
HR:156 bpm
4.7
2,000,000
15.8
4.4
Total:
4.1
Indirect:
3.5
NR
Negative
Yes
(packed RBC)
Yes
Zuccotti GV
et al. [31]
8 months
old
M
Pumpkin
seeds cross-
contaminated
with fava
beans
1
NR
No
NR
NR
Jaundice
NR
7.6
2,500,000
23
3.7
Total:
10.6
Indirect:
10.3
NR
Negative
Yes
(packed RBC)
Yes
(16 U/1012
RBC)
Nutrients 2023, 15, 343
6 of 19
Table 2. Cont.
Age
(Years Old)
Gen-
der
Triggering
Foods
Timing
(n. Days)
Previous
Episodes
First In-
gestion
Family
History
Ethnic-
ity
Signs & Symptoms
Vital Parameters
Hb
(g/dL)
Erythrocytes
(x mm3)
Ht
(%)
Reticulocytes
(%)
Serum
Bilirubin
(mg/dL)
Urinary
Urobilino-
gen
Coombs
Test
Transfusion
G6PD Test
Wadowski
B et al. [32]
2
M
Fava beans
and a
traditional
Chinese
herbal tea
1
NR
NR
NR
Chinese
Dark urine
Malaise
Jaundice Pallor
Sat02: 88%
4.1
NR
11.8
7
Total:
8.1
Direct: 0
NR
Negative
Yes
(packed RBC)
Yes
Clinical features of favism in pre- and adolescents
Mansoor S
[33]
12
M
Fava beans
0-14
NR
NR
NR
Israeli
Dark urine
Hepatomegaly
Pallor
Semicoma
Vomit
BT: 38 ◦C
BP: -
HR:140 bpm
3.0
2,360,000
NR
NR
10
NR
NR
Yes
(whole blood)
NR
12
M
Fava beans
NR
NR
NR
NR
Israeli
NR
NR
2.0
NR
NR
NR
NR
NR
NR
Yes
(whole blood)
NR
Holt Jm
and
Sladden RA
[34]
14
M
Fava beans
0–7
NR
NR
NR
Greek
Dark urine
Jaundice
Malaise
Systolic murmur
Vomit
NR
4.3
NR
NR
29
7.0
NR
NR
Yes
(whole blood)
Yes
(0.4 U)
10
M
Raw fava
beans
NR
NR
No
NR
Italian
Abdominal pain
Dark urine
Hepatomegaly
NR
6.7
NR
NR
12
1.0
NR
NR
NR
Yes
(63 U)
Oliveira S
et al. [35]
16
M
Fava beans
2
NR
Yes
Yes
European-
Caucasian
Abdominal pain
Dark urine
Hepatomegaly
Jaundice
Pallor
Splenomegaly
NR
NR
NR
NR
NR
NR
Positive
NR
No
Yes
(0.92 IU/g Hb)
Lau HK
et al. [36]
11.3
M
Fava beans
NR
NR
NR
NR
Hong
Kong
NR
NR
7.1
NR
NR
6,7
7.43
NR
NR
Yes
(packed RBCs)
NR
8.8
M
Fava beans
NR
NR
NR
NR
Hong
Kong
NR
NR
4.4
NR
NR
14,0
6.96
NR
NR
Yes
(packed RBCs)
NR
Clinical features of favism in adults
Stockley R
et al. [37]
56
F
Fava beans
2
Yes
No
NR
NR
NR
NR
10
NR
NR
NR
7.84
NR
NR
Yes
(packed RBCs)
Yes
(3.7 IU/g Hb)
41
F
Home-
grown fava
beans
1
NR
NR
NR
NR
NR
NR
9.6
NR
NR
NR
3.8
NR
Negative
NR
Yes
(3.4 IU/g Hb)
Hasler J
and
Lee S [38]
46
M
Raw fava
beans
1
NR
NR
NR
Middle
Eastern
Dark urine
Jaundice
Malaise
Nausea
Vomit
BT: 100.6 ◦F
BP: 120/70 mmHg
HR: 104 bpm
RR: 18/min
5.4
NR
15.8
21
Total:
7.5
NR
NR
Yes
(whole blood)
NR
Nutrients 2023, 15, 343
7 of 19
Table 2. Cont.
Age
(Years Old)
Gen-
der
Triggering
Foods
Timing
(n. Days)
Previous
Episodes
First In-
gestion
Family
History
Ethnic-
ity
Signs & Symptoms
Vital Parameters
Hb
(g/dL)
Erythrocytes
(x mm3)
Ht
(%)
Reticulocytes
(%)
Serum
Bilirubin
(mg/dL)
Urinary
Urobilino-
gen
Coombs
Test
Transfusion
G6PD Test
Hampl JS
et al. [39]
34
M
Fava beans
1
NR
NR
NR
Iraqi
Anemia
Dark urine
Jaundice
Renal failure
Vomit
BT: 99.3 ◦F
BP: 151/67 mmHg
HR: 117 bmp
RR: 18/min
3.6
900,000
9
NR
2.98
NR
N
Yes
(packed RBCs)
Yes
(2.6 U/g Hb)
Lim F et al.
[40]
44
F
Boiled fava
beans
1–2
NR
NR
No
NR
Dark urine
Edema
Malaise
Jaundice
BP: 110/90 mmHg
HR: 100 bmp
5.5
NR
NR
133 × 109/L
2.81
NR
NR
Yes
(whole blood)
Yes
(2.5 U/g Hb)
Soyuncu S
et al. [41]
56
M
Fava beans
3
NR
No
Don’t
know
NR
Dizziness
Syncope
BT: 37.2 ◦C
BP: 130/80 mmHg
HR: 116 bmp
RR: 20/min
8.4
NR
23.7
2.8
Total:8.53
Indirect:
0.39
NR
Negative
Yes
(packed RBCs)
Yes
Ata F et al.
[42]
56
M
Fava beans
NR
Yes
NR
NR
Qatari
Dizziness
Dyspnea
Jaundice
Pallor
Vomit
BP: 136/76 mmHg
HR: 93 bpm
Sat02: 70%
9.9
NR
NR
NR
Indirect:
3.51
NR
NR
Yes
(packed RBCs)
Yes
(23 mU/109
RBC)
Al-Dubai H
et al. [43]
47
M
Fava beans
2
NR
NR
NR
NR
Dark urine
Jaundice
BT: 38.5 ◦C
BP: 125/78 mmHg
HR: 117 bpm
RR: 20/min
Sat02: 88%
12
NR
NR
17.8
Total:
4.89
Direct:
0.65
NR
NR
No
Yes
(24 mU/109
RBC)
Hartigan JD
and
Gurnett TJ
[44]
74
M
Fava beans
0–1
Yes, twice
No
NR
NR
Dark urine
Hepatomegaly
Jaundice
Malaise
BT: 98.6 ◦F
BP: 120/60 mmHg
HR: 80 bpm
8.3
NR
25
NR
NR
NR
Negative
Yes
(whole blood)
NR
Torres CD
et al. [45]
67
M
Beans
NR
NR
NR
No
NR
Abdominal pain
Jaundice
Malaise
Renal failure
NR
4.9
NR
14.1
4.6
Total:
5.7
Indirect:
3.2
NR
Negative
Yes
(packed RBCs)
Yes
Legenda: BP, blood pressure; BT, body temperature; Hb, hemoglobin; HR, heart rate; Ht, hematocrit; NR, not reported; RBC, red blood cell; RR, respiratory rate; Sat02, saturation on
room air. Clinical parameters were evaluated according to the specific laboratory ranges given in the cited article.
Nutrients 2023, 15, 343
8 of 19
2. Materials and Methods
G6PD deficiency is the most prevalent enzymopathy in the world [2]. Globally, it is
the leading cause of neonatal jaundice and acute hemolytic crisis at any age, due to dietary
intake of fava beans. The WHO working group stressed the importance of education and
information as key tools for prevention of complications of G6PD deficiency [46]. As there
are few reviews that unify the knowledge produced to date on the topic of favism, we
summarized the literature to answer our research question on the influence of inter- and
intra-individual variability in the development of acute hemolytic anemia and several
factors related to the quantity, quality, and maturity of fava beans ingested, as well as age of
onset, to improve awareness on the topic. The authors A.B., M.M, and H.C. independently
reviewed all relevant literature produced from the earliest reports of cases of favism to the
present time (i.e., 1945–2021) in the form of case reports and case series. Original papers,
meta-analyses, clinical trials, and reviews were excluded. We imposed restrictions for
language (English, Italian, Spanish) and species (humans). We carried out a thorough
search for relevant papers on three databases: PubMed/MEDLINE, Scopus, and EMBASE.
The following keywords (alone and/or in combination) were used for the research: favism,
G6PD deficiency, acute hemolysis anemia, hemolysis, nutrition, age, fava beans, type,
quantity, ripeness. Results are reported in the form of a narrative review.
3. Results
3.1. Pregnant Women and Nursed Infants
Only a single case of a pregnant woman diagnosed with favism, whose fava bean
intake did not affect her pregnancy, was found in 1962. She was a 35-year-old woman in
the sixth month of pregnancy hospitalized for jaundice, caused by a generous portion (two
pounds) of fresh fava beans consumed over a day and a half. Physical examination revealed
jaundice, malaise, hepatomegaly, splenomegaly, and a systolic murmur; the laboratory
findings are shown in Table 2. In this case, no therapy was administered, but the woman
was forced to rest, and she was discharged after 16 days. Four months after the hemolytic
episode, the patient gave birth to a male who did not show any significant data. The
activity of G6PD in the mother’s erythrocytes was 3.7 units (normal 5 to 7 units), while in
the newborn it was 8.9 units, which is normal in children in the first few weeks of life. The
authors, Cahill KM and Lay AB [7], investigated the level of G6PD activity in the whole
family, finding a deficiency only in the mother of the patient.
In contrast to the case above, Mentzer WC and Collier E [8], in 1975, reported the case
of a woman with a history of fried fava bean intake during pregnancy, which played an
important role in the exacerbation of intrauterine hemolysis. This led to the death of the
infant two hours after birth, having never established spontaneous respirations. Family
history included a sister who was born with jaundice, a male maternal cousin treated
with phototherapy for neonatal jaundice, a maternal aunt who was anemic and presented
jaundice for one month at the age of 10, and finally the maternal grandmother who was
anemic. In this case, G6PD enzyme activity was investigated in the mother, who was found
to be heterozygous for G6PD deficiency but with no abnormal migrating band, and in the
child, who was also found to be G6PD deficient. The authors concluded that eating fava
beans, while being supplemented with ascorbic acid—considered a mild hemolytic agent
in subjects with G6PD deficiency—and having a viral in utero infection, may be responsible
for the intrauterine hemolysis.
Fortunately, a pregnant woman’s intake of fava beans when the baby has a G6PD
deficiency does not always result in a fatal outcome, as shown in the case reported by
Corchia C et al. [9] in 1995. A 2-hour-old female infant, born at 37 weeks of gestation by
cesarean section, developed acute hemolytic anemia (AHA) after her mother’s ingestion
of cooked dried fava beans five days before delivery. The treatment of the child with a
whole blood transfusion and phototherapy lead to a complete remission of symptoms,
and so she was discharged on the 11th day of hospitalization in good clinical condition.
G6PD activity investigated after four months reported a 4.61 U/g Hb (normal concentra-
Nutrients 2023, 15, 343
9 of 19
tion, 6.73 +/−2.10). G6PD activity was investigated in the entire family and reported the
following values: 5.9 U/g Hb in the mother, 7.10 U/g Hb in the father, 0 and 5.4 U/g Hb in
the mother’s two brothers, respectively, and 4.68 U/g Hb in the maternal grandmother.
Some case reports and case series describe the effects of fava bean ingestion by lactating
women whose children are deficient in the G6PD enzyme, and developed varying degrees
of severity in their symptoms.
In 1956, Casper J and Shulman J [10] reported the case of a 6-month-old Yemeni
male infant who died three days after admission to the pediatric ward for AHA. Jaundice,
hepatomegaly, pallor, vomit, and dark urine began two days after his mother’s ingestion
of fava beans. On the day of admission, urination ceased completely, causing an increase
in blood urea to 276 mg/100 mL. The infant was treated with a transfusion of 200 mL of
blood, but the outcome was negative. He was diagnosed with favism, even though the
mother had never shown any signs of G6PD deficiency, on the basis of the history of fava
bean consumption and laboratory findings.
Emanuel B and Schoenfeld A [11] reported, in 1961, the case of an Egyptian female
breastfed infant whose mother ate fava beans three days before admission. On physical
examination, the infant showed malaise, jaundiced skin, pale mucous membranes, hep-
atomegaly and splenomegaly, and dark urine with increased urobilinogen content (1:220).
Since the erythrocyte count was 1,000,000/mm3, the child was transfused twice with whole
blood resulting in a return to the normal range of clinical parameters and discharge. In this
case, broad beans were a food regularly present in the family diet and there was no history
of diagnosed favism. The authors had investigated the level of reduced glutathione after
incubation of blood with acetylphenylhydrazine, a characteristic erythrocyte abnormality
in favism, which was found to be 41 mg per 100 cc of erythrocytes (normal value: 70 mg
per 100 cc). This single value was not enough for a diagnosis of enzymatic abnormality,
but it was proven to be a homozygous G6PD deficiency six weeks after the initial episode,
thanks to a Beutler test.
Finally, in 1971, Taj-Eldin S [12] reported four cases of diagnosed favism in exclusively
breast-fed infants who developed AHA. The first one, a four-month-old Arab boy, was
admitted four days after his mother ate boiled fava beans. On physical examination,
he showed pallor, malaise, jaundice, hepatomegaly, and dark urine. Laboratory findings
showed erythrocytes 1,480,000/mm3, hemoglobin 3.8 g/dL, reticulocytes 7%, total bilirubin
4.2 mg/dL, indirect bilirubin 3.6 mg/dL, and a negative indirect Coombs test. The child
was treated with a whole blood transfusion, followed by a complete recovery. The other
three reported cases were all Arab boys, who first showed symptoms 2–3 days after their
mothers ate fava beans. On physical examination, jaundice, dark urine, hepatomegaly
or splenomegaly, and pallor were noted. The laboratory findings showed, respectively:
hemoglobin 4.7, 5.2 and 4.0 g/dL; erythrocytes 2,100,000, 1,900,000 and 1,210,000/mm3;
reticulocytes 6%, 12% and 10%; total bilirubin 3.8, 4.5 and 5.0 mg/dL. Urobilinogen was
found positive in the urine in case 1 and case 3. No data on the treatment of the latter three
cases are reported. G6PD deficiency was demonstrated in all cases with the Motulsky dye
test, strongly suggesting the diagnosis.
The symptom spectrum for this age category presented systolic murmurs and fatal
renal failure, in addition to the classic symptoms. The time between the ingestion of the
triggering substances and the onset of symptoms ranges from a minimum of 24 hours to
a maximum of 5 days, and more days are needed for hospitalization. Furthermore, the
two reported deaths underline the fact that favic attacks are more commonly severe in
children due to the high ratio between ingested causative agents and body mass, and in
male children whose mothers are not aware that they are healthy carriers of the recessive
gene. Even though the patients are infants, there is no mention of whether or not they had
experienced other episodes later in life. All the clinical features of favism in this age group
are summarized in Table 2.
Nutrients 2023, 15, 343
10 of 19
3.2. Children (from Weaning to 11 Years)
In children, several papers reported favism patients of Italian descent.
One of the first reported cases of favism was in 1947, described by Wharton HJ
and Duesselmann W [13]. The patient was a 3.5-year-old male child, who was admitted
to the hospital for jaundice and dark urine for 16 h. The patient’s mother referred to
the fact that on the day of the onset of the symptoms, the child had a large meal of
fava beans, and that no such episode had ever happened to any of the family members.
The physical examination described malaise, AHA, jaundice, pale mucous membranes
and conjunctivae, and hepatomegaly. The laboratory examinations showed hemoglobin
4.2 g/dL, erythrocytes 1,140,000/mm3, and reticulocytes 4.2%; while, urine tests were
positive for urobilinogen, bile, and albumin. In the following days, several transfusions
were administered which led to a consistent change in hematochemical values and thus a
rapid improvement in general condition. The diagnosis was made based on the history of
fava bean consumption and on the laboratory findings. The patient was discharged on the
eighth day without jaundice or anemia.
Rosen Ap and Scanlan JJ [14] reported in 1948 the case of a 5-year-old boy of Italian
origins who had been hospitalized with abdominal pain, dark urine, and jaundice for
30 h. Two years earlier, the child had experienced the same symptoms, which resolved
spontaneously without medication within two weeks. The patient was treated with a
transfusion of whole blood and 5% glucose in water and saline. Following treatment, the
clinical picture gradually improved. The onset of symptoms was traced back to the intake
of four large plates of broad beans the previous day; also, the boy had eaten fava beans
two years before, when the previous jaundice attack occurred. The diagnosis of favism
was made by the authors based on the history of attacks following fava bean ingestion, as
no fava bean sensitivity tests were available at the time. Additionally, the mother refused
permission to give the child some fava beans to stimulate a reaction.
Similarly, in the case reported by Pickering DE and Hurwitz S [15] in 1951, there was
no test available to investigate G6PD deficiency. The patient was a 28-month-old male child
of Italian origin. On physical examination, he presented with jaundice, malaise, irritability,
fever, vomiting, dark urine, yellowish sclerae, pale membranes, and a systolic murmur.
The onset of symptoms was associated with the consumption of broad beans 36 h earlier.
Treatment consisted of a whole blood transfusion, followed by an immediate improvement
in condition; hemolysis stopped approximately 48 h after the onset of jaundice. The
authors tried to use scratch tests with antigens prepared from fresh broad beans to prove
the diagnosis, based on fava bean consumption, signs, and symptoms, but the result
was negative.
In 1953, Larkin VD [16] reported the case of a 1-year-old girl of Italian origin with
a one-month history of pallor in the eyes, ears, and lips following the ingestion of fava
beans for two or three consecutive days. Laboratory findings showed hemoglobin 6.8 g/dL,
erythrocytes 3,460,000/mm3, and a negative Coombs test. The patient was treated with
vitamin B12, folate, and iron, and her color improved rapidly within a week. She was
diagnosed with favism based on signs and symptoms.
In the same year, Diggle JH [18] reported two cases with different degrees of symp-
tomatology in children of Cypriot origin. The first case was a 3.5-year-old male child
admitted 30 h after the onset of symptoms, such as dark urine, abdominal pain, pallor,
and jaundice. Physical examination revealed AHA, jaundice, and systolic murmur, and
laboratory findings showed hemoglobin of 4.35 g/dL and a negative Coombs test. On
spectroscopy examination, methemoglobin was found. Treatment consisted of whole blood
transfusions, which led to improvement and discharge on the eighth day of hospitalization.
The symptoms were associated with the ingestion of a plate full of broad beans on the
day of the onset of the symptoms; based on this, and on the presence of typical signs and
symptoms, the diagnosis of favism was made. Other cases of anemia were not reported in
the mother’s, nor in the father’s family. The second case was a 9.5-year-old child admitted
to the hospital with jaundice and anemia because of eating broad beans. The parents
Nutrients 2023, 15, 343
11 of 19
reported that he had a similar a symptomatological picture two years earlier. On admission,
the physical examination revealed moderate jaundice, malaise, vomiting, and anemia; the
hematochemical examination showed a hemoglobin of 9.9 g/dL and an erythrocyte count
of 2,320,000/mm3, reticulocytes 8%, a serum bilirubin content of 6.8 mg/dL, and a negative
Coombs test. No transfusion was necessary, and the clinical picture resolved spontaneously
within four weeks. The authors prescribed an ounce of cooked broad beans for the patient,
but this did not affect the hemoglobin level, so this association seems inconclusive.
A few years later, in 1957, Tolmas HC [17] reported the case of a 2.5-year-old Italian
male child admitted to the hospital for dark urine, jaundice, and pallor following the
ingestion of broad beans two days earlier. The family history revealed that his maternal
great-grandfather and paternal uncle also manifested such symptoms following the inges-
tion of broad beans. The diagnosis was made based on family history, signs, and symptoms.
The patient was treated with dextrose in distilled water and a whole blood transfusion, as
well as hydrocortisone, ascorbic acid, vitamin K, penicillin, and streptomycin. The patient’s
condition improved continuously over the following days, and he was discharged on day
three in good general condition.
Three papers analyze the cases of patients who have been hospitalized multiple times
for symptoms developed after the ingestion of fava beans. Firstly, in 1955, McCarthy
OR [19] reported the most severe exacerbation of favism in a 9-year-old British child who
had several previous episodes of jaundice, always preceded by a fava bean meal. He
was hospitalized for jaundice that appeared the same day he ingested fava beans, with
shivers, malaise, and vomiting. The family history reported that the brother of the child’s
mother also used to have jaundice and malaise whenever he ate broad beans. On physical
examination, he had malaise, vomiting, jaundice, yellowish sclerae, and hepatomegaly.
Laboratory tests are shown in Table 2. The jaundice resolved within 24 h and there were no
longer other signs or symptoms, so the child was discharged with a diagnosis of favism
and with the warning never to eat broad beans again. Then, in 1958, Brooks EA et al. [20]
reported the case of a 3-year-old female child with abdominal pain, vomiting, and dark
urine, pallor, coryza, and jaundice. The patient was treated with a whole blood transfusion,
which led to a general improvement in clinical condition and hematochemical parameters.
The patient was then readmitted to the hospital five months after the first episode with the
same symptoms, although less pronounced than before. This second episode was resolved
in 10 days, with no need for transfusion. The patient was discharged after the parents
were warned not to let the child eat broad beans anymore. The author found it interesting
that the osmotic fragility of the red blood cells of the patient’s father, and sister, slightly
decreased. It should be noted that this article was written in 1958 when favism had not yet
been discovered. Finally, in 1960, Gower ND and Frommer E [21] reported the case of a
3-year-old Cypriot male child admitted to the hospital with dark urine and pallor for 24 h,
and several episodes of vomiting, pallor, malaise, jaundice, enlarged tonsils and lymph
nodes. Treatment consisted of a transfusion of packed red blood cells, as well as cortisone,
prednisolone, and penicillin. Following treatment, the patient’s clinical condition improved
rapidly, and he was discharged on day 11 of hospitalization. The patient was seen later
after a few days of sore throat and one day of dark urine, following the ingestion of broad
beans the day before, but recovery was rapid and did not require a transfusion. At first,
the author ruled out a diagnosis of mild congenital hemolytic anemia, and even after the
second hospitalization, investigations revealed no red blood cell defects; however, after full
recovery, the authors were able to demonstrate that the red blood cells behaved abnormally
after incubation with acetylphenylhydrazine, and thus a diagnosis of favism was made.
Discombe G and Mestitz W [22] reported, in 1956, the case of a 2.5-year-old girl of
Middle-Eastern descent with a history of 1–2 days of fever, malaise, and yellowish eyes.
The patient was treated with a transfusion of packed red cells, followed by continuous
improvement until complete remission on day seven. Symptoms started after she ingested
fava beans either 1–2 days before and on the same day. The authors emphasize that there
Nutrients 2023, 15, 343
12 of 19
was no evidence that this was a favic attack and that it would be unethical to try to prove
this by inducing it.
Two particular cases of severe ophthalmological complications following favism were
reported by Choremis C et al. [23] in 1960. The first case was a 3-year-old boy admitted
to the hospital for malaise, vomiting, dark urine, and jaundice after eating broad beans
the day before. On admission, the patient was comatose, with spastic legs, a plantar reflex
in extension, hepatomegaly, and splenomegaly. Laboratory findings showed hemoglobin
6 g/dL, erythrocytes 2,300,000/mm3, serum bilirubin 5.8 mg/dL, and indirect bilirubin
2.0 mg/dL. Treatment consisted of several daily transfusions of whole blood. On the third
day of admission, the general condition worsened with the appearance of ecchymoses,
but in the following days, the patient came out of the coma and the hematochemical
parameters improved, but he was completely blind. On ophthalmological examination, the
pupils were mydriatic and unresponsive to light; there were diffuse retinal and pre-retinal
hemorrhages in the posterior pole and in the hyaloid body, explained by the authors as a
consequence of the generalized hemorrhagic state due to favism. The prognosis was poor
due to the hemorrhages in the hyaloid body. The second case was a 6-year-old boy admitted
to the hospital for blindness, which developed progressively two days after an attack of
favism, and apparently resolved without treatment. On admission, the results of the
physical examination and laboratory tests were essentially normal. On ophthalmological
examination, edema and blurring of the disc margins, as well as constriction of the retinal
vessels with small hemorrhages, were found, which, together with the sudden bilateral
loss of vision, might be associated with the acute hemolytic syndrome that had occurred
7 days earlier due to favism. The authors reported that post-hemolytic anemia, together
with a trigger factor (the one responsible for the hemolysis), may have caused severe
ocular involvement.
In 1966, Stewart AG et al. [24] reported the first case of favism in Canada. A 4-year-
old Norwegian-Ukrainian male complained of malaise, abdominal pain, anorexia, dark
urine, and several episodes of vomit. The physical examination showed a semi-comatose
child with jaundice, pallor, and yellowish eyes. The treatment consisted of a whole blood
transfusion, intravenous fluids, and methylprednisolone. The patient was oliguric until the
third day of hospitalization when diuresis started to improve rapidly. After one week, he
was discharged in good condition. The onset of symptoms occurred one day after a meal of
broad beans, cooked and raw. This was not the first time the child had eaten broad beans,
but it is not clear whether previous ingestions were followed by the disease. Five months
after the episode, the G6PD activity was found to be 0 U/g Hb.
Some years later, in 1989, Wong WY et al. [25] reported the case of a 2.5-year-old
male child who presented with dark urine, pallor, and a reduced appetite. On physical
examination, no relevant parameters were found, other than a grade 1/6 systolic murmur.
Red cell transfusion resulted in complete remission in four days. Because of the language
barrier, the authors report that the parents initially denied ingesting fava beans, but later
reported that the child had eaten a common Asian snack made from seed pods of the fava
plant. A laboratory test held several months later showed a 0 IU/g Hb of G6PD enzyme
activity (normal range, 7.9 to 16.3 IU/g Hb).
Galiano S et al. [26] reported three cases of favic attacks due to variant A−in 1990.
The first case was of a 19-month-old Italian male child admitted for dark urine and malaise,
three days after the ingestion of broad beans. Four months later, G6PD activity was 10% of
the normal value. The second case was of a 4-year-old black male admitted to the pediatric
clinic due to the appearance of dark urine, anemia, vomiting, and headache, 60 h after
ingesting beans; the laboratory tests revealed a hemoglobin concentration of 5.1 g/dL and
reticulocytosis of 9%. Investigations on the activity of the G6PD reported a value equal to
12% of normal. The latest reported case was a six-month-old Anglo-Jamaican girl admitted
to the hospital for jaundice, paleness, and dark urine, 24 h after the first ingestion of broad
beans; she also ingested them on the day of admission. Her father was found to have 7%
Nutrients 2023, 15, 343
13 of 19
of normal G6PD enzyme activity, so the authors concluded that he was heterozygous for
G6PD deficiency, and diagnosed favism. No data were reported on the treatment used.
More recently, in 2011, Odièvre MH et al. [27] reported the case of a 6-year-old Algerian
male presenting with symptomatic methemoglobinemia, meningitis, fever, headache, vomit,
cyanosis of the lips, and 80% oxygen saturation, resistant to oxygen therapy. The day after
admission, the patient was pale, tachycardic, and passed dark urine, while hemoglobin had
dropped to 6.0 g/dL and the methemoglobin fraction had increased to 8.7%. Treatment
consisted of an oxygen mask and a transfusion of packed red blood cells. Upon questioning,
it was discovered that the child had eaten broad beans the day before, and that there was a
family history of G6PD deficiency. A laboratory examination of the child’s blood revealed
that he was hemizygous for variant A- with an enzyme activity of 6 U/g Hb (normal
range: 8–22 U/g Hb).
Additionally, Leunbach TL et al. [28] reported in 2014 two cases of methemoglobine-
mia. The first was a 4-year-old Iraqi male admitted with fever, fatigue, AHA, jaundice, and
cyanosis with SpO2 74%, which developed two days after fava bean ingestion. Oxygen
therapy followed by a transfusion made the cyanosis disappear and raised the SpO2 to 85%.
The hemolytic episode resolved without any problems and G6PD deficiency was demon-
strated to be 0.08 kU/mol (normal value: 0.51–1.32 kU/mol). The second case reported was
a 6-year-old Iraqi male without cyanosis, but with SpO2 at 78%, resistant to supplemental
oxygen, and AHA, which developed the day after the ingestion of broad beans. Again, a
packed red blood cell transfusion was performed, which led to an improvement in SpO2
and all chemical parameters over the next two days. In this case, favism was diagnosed
with a G6PD activity <0.10 kU/mol (normal value: 0.51–1.32 kU/mol).
In 2013, Mohamed M and Els I [29] reported the case of a 15-month-old Chinese male
child admitted to the emergency room for malaise, jaundice, paleness, and yellow sclera,
which lasted for 24 h following the ingestion of bean soup. The child had hemizygous
G6PD deficiency, with an assay of 3.2 IU/g Hb, lower with respect to the normal range
(8.8–17.9 IU/g Hb).
One year later, in 2014, Verdugo LP et al. [30] described the severe case of a 31-month-
old male child admitted to the pediatric critical care unit for malaise, abdominal pain,
paleness, fever, and vomiting. Upon admission, laboratory tests showed AHA: hemoglobin
4.7 g/dL, hematocrit 15.8%, erythrocytes 2,000,000/mm3, reticulocytes 4.4%, total bilirubin
4.11 mg/dL and indirect 3.53 mg/dL, Coombs test negative. The manifestation of symp-
toms occurred 48 h after the ingestion of fresh broad beans. The treatment consisted of a
transfusion of packed red blood cells, intravenous hydration, and folic acid, which led to
a progressive improvement in the laboratory tests and therefore the clinical condition. A
Toenz and Bretke test confirmed the G6PD deficiency.
In the same year, Zuccotti GV et al. [31] reported the case of an 8-month-old male child,
weaned, who developed jaundice due to favism. The examination revealed hemoglobin
7.6 g/dL, erythrocytes 2,500,000/mm3, hematocrit 23%, reticulocytes 3.7%, total bilirubin
10.6 mg/dL and unconjugated 10.3 mg/dL; while, a second sample revealed an even greater
AHA: hemoglobin 5.6 mg/dL, hematocrit 17.7%, LDH 739U/L, and Coombs test was nega-
tive. The child was treated with a packed red cell transfusion. A laboratory examination
revealed a G6PD activity value of 16 U/1012 RBC (reference ranges: 146–376 U/1012 RBC).
The authors speculated that the cause of AHA was cross-contaminated pumpkin seeds
with broad beans. The contamination was proven when fava bean DNA was found in the
frozen pumpkin DNA, extracted from the sample eaten by the child.
Wadowski B et al. [32] reported, in 2016, the case of a 2-year-old Chinese male child ad-
mitted to the hospital with paleness, malaise, and dark urine, as well as a one-week history
of intermittent fever. The patient was treated with multiple packed red cell transfusions,
which resulted in the resolution of the symptoms. Thanks to an interpreter, it was possible
to identify that the child ate a cup of broad beans and drank traditional Chinese tea, one
day before the onset of symptoms, and a test confirmed the G6PD deficiency.
Nutrients 2023, 15, 343
14 of 19
The spectrum of clinical features in this age category presents a wide variety: systolic
murmur, semi-coma or coma state, methemoglobinemia, and partial or total loss of vision,
in addition to the classic symptoms. The time elapsed between the intake of fava beans and
the onset of symptoms varies from 1 to 3 days. Only two articles reported the G6PD variant
(i.e., A−), which falls in class B according to the WHO classification [1], corresponding to a
median activity of less than 45% of normal and acute or triggered hemolysis. In other cases,
the variant is not described. Due to the lack of data and the large number of variants of the
allele discovered up to now, we cannot associate symptoms with a specific variant. In three
reports, patients were hospitalized twice for fava bean ingestion, while in all other reports
it is not mentioned whether the children had further attacks. All the characteristics of this
age group are summarized in Table 2.
3.3. Pre- and Adolescents (11–18 Years)
In 1955, Mansoor D. [33] reported two cases of favism in Israel. The first case was
a 12-year-old male admitted in a semi-comatose state, with no plantar response but eye
and tendon reflexes present. On physical examination, the patient presented with dark
urine, pallor, hepatomegaly, limbs with spasmodic contractions, and profuse sweating. The
symptoms were associated with the ingestion of broad beans for two consecutive weeks,
which together with the presence of typical signs and symptoms, led to the diagnosis of
favism. The patient was treated with several transfusions, followed by an improvement
in hemoglobin from 3.0 g/dL on day 1 to 7.0 g/dL after the second transfusion. He was
discharged on the 8th day, after an uneventful recovery. As in the former case, the latter
was a 12-year-old male, with symptoms triggered by the ingestion of broad beans. As the
patient had a hemoglobin of 2.0 g/dL, he was treated with two transfusions and discharged
after two weeks with a diagnosis of favism.
Holt JM and Sladden RA [34] reported, in 1965, two cases, one which might have
proved fatal. The first case was a 14-year-old male of Greek origins admitted to the hospital
for extreme tiredness, noises in the ears, a fainting episode, several episodes of vomit,
malaise, jaundice, weakness, dark urine, systolic murmur, extensor plantar responses, and
semi-coma. The G6PD level was 0.4 units (normal range 2.1–4.2 units), and symptoms
followed the ingestion of a large quantity of broad beans, eaten daily for a week; a diagnosis
of favism was therefore made. The treatment consisted of a whole blood transfusion, which
led to an improvement in general condition. The second case was a 10-year-old Italian male
admitted to the hospital for epigastric pain and malaise. On physical examination, he had
malaise, yellowish sclerae, dark urine, and hepatomegaly. The erythrocyte G6PD level was
found to be 63 units (normal range: 150–217 units) and so the diagnosis was confirmed.
After that, the patient was discharged on the sixth day of recovery when his hemoglobin
level was raised to 9.9 g/dL without any treatment. Upon questioning, it turned out that
broad beans were a regular part of the family’s diet and that he had never had any effects,
but this time, for the first time, the child had eaten them raw.
Oliveira S et al. [35] reported, in 2000, the case of a 16-year-old European-Caucasian
male with dark urine, fever, and abdominal pain that developed two days after ingesting
broad beans for the first time. On physical examination, jaundice, pallor, hepatomegaly and
splenomegaly, and a painful hypogastric region were present. Blood examination revealed
AHA, unconjugated hyperbilirubinemia, elevated LDH, bilirubinuria, and hemoglobinuria.
On family history, the mother reported that she had also had a similar episode due to the
ingestion of broad beans many years earlier. As the child refused a blood transfusion, the
only treatment was intravenous hydration. During the first two days, there was a drop in
hemoglobin, but on the third day (the fifth after the beans were ingested), the laboratory
parameters started to improve. Laboratory tests on the patient’s blood and that of his family
members revealed the presence of a G6PD deficiency in the patient himself (0.92 IU/g Hb;
normal range: 5–7.1 IU/g Hb), his mother, and two of his brothers.
In 2006, Lau HK et al. [36] published a retrospective review of six Hong Kong male
patients admitted to the Department of Pediatrics of the Tuen Men Hospital from March
Nutrients 2023, 15, 343
15 of 19
1993 to February 2005, with acute massive hemolysis with a neonatal diagnosis of G6PD
deficiency. Two of them had experienced a hemolytic crisis after the ingestion of fava beans,
while the other four developed symptoms after exposure to mothballs (n = 1), treatment
with herbal medicine or intramuscular injection of unknown nature (n = 2), and upper
respiratory tract infection (n = 1). The first one was an 11.3-year-old, and the second one
was an 8.8-year-old. Both of them were admitted to the pediatric intensive care unit and an
erythrocyte transfusion was performed (5 units and 1 unit, respectively). They all made a
complete recovery.
The severity of symptoms in this age category varies from near-fatal episodes, probably
due to the large quantity of fava beans ingested, to very mild symptoms that resolved
spontaneously. The time elapsed between fava bean ingestion and the onset of symptoms
varies within a narrow range of 1 or 2 days; in two cases, the onset of the hemolytic attack
followed after a week or more of consecutive fava bean ingestion. In only one case the
degree of deficiency was detected. All the clinical features of this age group are summarized
in Table 2.
3.4. Adults (>18 Years)
We found some cases of favism in adulthood from 34 years old to 74 years old.
Stockley R et al. [37] first reported favism in adults in 1985. The authors described two
cases of women with attacks of favism due to fava bean intake, two days before and one
day before symptom onset, respectively. The first woman, aged 56, had eaten fava beans
several times before, but never as many as this time; she recalled an episode of AHA and
jaundice 10 years earlier, as well as having had jaundice as a child. Laboratory tests showed
a hemoglobin level of 10 g/dL and serum bilirubin of 7.84 mg/dL, while G6PD enzyme
activity was found to be low at 3.7 IU/g Hb (normal range: 4.6–13.5). Treatment consisted
of packed red blood cell transfusion and hydration, which resulted in the resolution of
jaundice in four days. The second woman, aged 41, presented with a 24 h history of
jaundice and dark urine; in this case, it is not reported whether fava beans had ever been
ingested before, or whether these symptoms had been present in the past. Laboratory tests
showed a hemoglobin level of 9.6 g/dL and serum bilirubin of 3.8 mg/dL, and a negative
Coombs test. The G6PD enzyme level was reduced to 2.1 IU/g Hb, but after two weeks was
found to be 3.4 IU/g Hb. Jaundice and general clinical conditions resolved spontaneously.
Hasler J and Lee S [38] reported, in 1993, the case of a 46-year-old Middle-Eastern
man with a history of several days of malaise, intermittent fever, persistent nausea, and
vomiting, as well as myalgia and arthralgia of the left shoulder and lower spine, due to
the ingestion of a large amount of raw fava beans, six to eight cocktails, and many glasses
of wine at a party the day before the onset of symptoms. On physical examination, the
patient presented jaundice, mild distress, dark and intermittently bloody urine, yellowish
eyes, and sinus tachycardia without murmur. Laboratory results showed hemoglobin
5.4 g/dL, hematocrit 15.8%, reticulocytes 21%, total bilirubin 7.5 mg/dL, LDH 1682 U/L.
He was treated with oxygen supplementation, intravenous normal saline, and a whole
blood transfusion. Recovery was not difficult, and the patient was discharged in good
general condition with a diagnosis of favism, based on typical signs and symptoms.
In 1997, Hampl JS et al. [39] reported the case of a 34-year-old Iraqi male who de-
veloped AHA, renal failure, and jaundice the day after eating broad beans. The patient
took Vick Formula 44 to treat an episode of vomiting, fever, and anorexia, which occurred
four days before admission. Physical examination revealed dark urine and yellowish eyes,
and a dry mouth. Following laboratory results (hemoglobin: 3.6 mg/dL, erythrocytes:
900,000/mm3, hematocrit: 9%, serum bilirubin: 2.98 mg/dL) and analysis of the G6PD
enzyme level, which was 2.6 U/g Hb (normal range: 4.6–13.5 U/g Hb), the patient was
diagnosed with favism. The patient was treated with hemodialysis and transfusions of
packed red blood cells, in addition to oral folate and vitamin supplements. He continued
hemodialysis for 2 weeks after his discharge.
Nutrients 2023, 15, 343
16 of 19
Lim F et al. [40] reported, in 2005, the case of a 44-year-old female who presented with
malaise, vomiting, yellowish eyes, and dark urine after consuming two meals of boiled
fava beans, two days before the onset of symptoms and even on the same day. Laboratory
findings showed anemia and reticulocytosis. Physical examination showed jaundice and
ankle edema. The patient was treated with a whole blood transfusion. The family history
showed no cases of jaundice or AHA, but during the laboratory investigation for the
analysis of G6PD enzyme activity, she was found to be heterozygous for the 563 C > T
mutation of the Mediterranean variant, with an activity of 2.5 U/g Hb (normal range:
4.6–13.5 U/g Hb).
More recently, in 2011, Soyuncu S et al. [41] reported the case of a 56-year-old man with
a 2 day history of yellowish eyes, dizziness, and recurrent attacks of syncope, hemoglobin
8.4 g/dL and hematocrit 23.7%. The G6PD level was low and, although it was not the first
time the patient had eaten fava beans, in this case, it caused an exacerbation of the reported
symptoms. Treatment consisted of a transfusion of packed red blood cells, which improved
the general clinical condition.
In 2021, two articles were published reporting favism attacks in adults. Ata F et al. [42]
reported the case of a 56-year-old Qatari man with dyspnea, dizziness, and vomit that
developed after a large meal of fava beans—a food that had been consumed previously,
although in smaller quantities. On physical examination, he presented with pallor, jaundice,
low oxygen saturation, resistance to supplementation, and a methemoglobin level of 5.6%,
for which he received intravenous (IV) methylene blue 80 mg. Laboratory tests revealed a
hemoglobin level of 9.9 gm/dL, which decreased to 7 g/dL after 24 h. He was treated with
a red blood cell transfusion, which did not stop the drop in hemoglobin. He was diagnosed
with G6PD deficiency (23 mU/109 RBC, normal value: 224–517 mU/109 RBC), and was
discharged as he became asymptomatic on the fifth day. Al-Dubai H et al. [43] reported the
case of a 47-year-old man with a 3 day history of yellowish eyes and dark urine, arising
two days after a medium-sized plate of broad beans. On physical examination, there was
jaundice, methemoglobin level of 3.6%, and a decreased oxygen saturation, which was
resistant to supplementation. G6PD activity was found to be low (24 mU/109 RBC, normal
value: 191–327 mU/109 RBC), and so a diagnosis of G6PD deficiency was made. The
treatment consisted of paracetamol and supplemental oxygen, but no transfusion was
required. He was discharged after two days, after being counseled on food and drugs
to avoid.
We found only two cases in which the attack of favism developed in elderly age: in the
first case, the patient had already had two similar episodes, 12 years and 6 years earlier, and
developed the classic symptoms that were resolved using whole blood transfusions; while
in the second case, the patient had never had previous episodes and the attack of hemolysis
led to severe renal failure. The clinical aspects are discussed in more detail below.
In 1959, Hartigan JD and Gurnett TJ [44] reported the case of a 74-year-old male, who
developed dark urine, weakness, jaundice, malaise, and fever, after a dinner of broad beans.
He had experienced two previous episodes with such symptoms, which led to the diagnosis
of favism.
In 2012, Torres C D et al. [45] reported the case of a 67-year-old man with a 2 day
history of abdominal pain, jaundice, choluria, and malaise that developed after eating
beans. Physical examination showed oliguric acute renal failure, requiring dialysis support
(see Table 2). Three months after discharge, G6PD activity was investigated with a Toenz
and Betke test, which showed undetectable enzyme activity. There was no family history
of favism.
To summarize, in adults (Table 2), the scenarios reported include the following:
1.
Adults who eat broad beans for the first time in adulthood and develop symptoms
associated with favism.
2.
Adults who have eaten broad beans before but without any symptoms associated
with favism, which, on the other hand, are now present in the reported case. In this
Nutrients 2023, 15, 343
17 of 19
case, exacerbation of symptoms is usually associated with a much higher fava bean
intake than the dose normally taken.
3.
Adults who have eaten broad beans and have previously experienced symptoms
associated with favism.
Moreover, the spectrum of symptoms includes renal failure, of different degrees,
in addition to the classic ones. Treatment can also vary widely: from requiring several
transfusions and hemodialysis, to being self-limiting and resolving on its own. One article
reported the G6PD variant (i.e., Mediterranean), with a 563 C > T mutation, which again
falls into class B, just like the A- variant previously described; while in a few cases, the
authors investigated the G6PD activity, which was always found to be low or absent.
4. Conclusions
Age of onset seems to play an important role in clinical presentation, but it is not
certain whether this exceeds the severity of the enzymatic deficiency itself. The erratic
feature of the gene is the factor responsible for the wide variability in symptom exacerbation.
As reported in several cases, the onset of symptoms is not always concomitant with the
first ever fava bean ingestion, but it is also true that it usually appears when the amount
of fava beans ingested is greater than the amount previously eaten, or when fava beans
are eaten continuously for several days. This is especially evident in youngest children or
pregnant women when the severity of the symptoms could be explained by the unbalanced
ratio between volume of beans ingested and the patient’s body mass.
The clinical picture described has always an underlying state of acute hemolytic
anemia, which is one of the most specific symptoms of favism. The laboratory findings
are characterized by anemia, with a very wide range of hemoglobin (2.0–12.0 mg/dL),
reticulocytosis (from 2% up to 65%), which stands for an increased bone marrow activity
trying to compensate the hemolysis, elevated unconjugated bilirubin level, and sometimes
by the presence of urinary urobilinogen and of methemoglobinemia.
The symptomatology spectrum encloses specific, aspecific and rare symptoms. The
specific symptoms for favic attacks were jaundice, developed due to the increased bilirubin
following increased erythrocyte depletion, and therefore splenomegaly, sometimes even
hepatomegaly, discolored urine, tachycardia, and pallor. The aspecific symptoms were
abdominal pain, malaise, vomiting, nausea, and dizziness. From our review, we found an
association between rare symptoms and age of onset:
-
two cases of death were reported, probably due to the high ratio between quantity of
fava beans ingested and the weight of the patient (infants);
-
two cases of sight problems and blindness were described as a complication of the
favic attack, both in children;
-
several cases of systolic murmur were observed in infants, children, and adolescents;
-
three cases of renal failure were found, in adults, to be associated with favism.
With the fatal exception of death in infants, the symptomatology is self-limited and
does not release sequelae, but in most cases hospitalization and transfusion, of whole blood
or packed red blood cells, are required.
When favism is diagnosed, it is more common to detect the severity of the deficit than
the detection of the variant itself. Nevertheless, some considerations can be made. In the
reported cases, the Gd gene variants can be categorized into class B, corresponding to cases
in which a hemolytic crisis developed, and class C, for those less severe cases in which
hemolytic anemia was not present.
The type of fava beans eaten also plays a role in the likelihood of symptom onset:
raw fava beans are more likely to induce the crisis, than cooked, frozen, or canned ones;
in addition, the amount of glucosides is directly proportional to degree of ripeness, so
the more unripe the fava beans, the less the amount of vicine and convicine, and thus the
lower the risk of the crisis onset. Despite several professional and patient associations
educating G6PD deficient patients to avoid all kinds of beans and pulses and several other
medications or products [47], no consideration can be made from the results of the present
Nutrients 2023, 15, 343
18 of 19
review. Nonetheless, we feel that further studies should better investigate the effect of
the consumption of pulses other that fava beans on G6PD deficient patients with different
enzymatic variants.
As for fava bean consumption, available evidence suggests the following: if the
enzyme deficiency is known, the best strategy to avoid the onset of a favic crisis is the
complete elimination of fava beans from one’s diet; on the other hand, if the deficiency
is not known, due to lack of family history of anemia, jaundice, or other symptoms that
may resemble favism, some precautions can be taken: avoid very large fava bean meals,
preferably consume fava beans that are not too ripe, and choose frozen, boiled, or canned
versions; however, none of these precautions give a complete guarantee of the absence
of danger.
Finally, a small mention must be made of the importance of avoiding cross-contamination;
in fact, a case described the harmful exacerbation of symptoms due to the ingestion of
pumpkin seeds contaminated with broad beans. Therefore, in the presence of G6PD
deficiency carriers, it is necessary to pay particular attention to the preparation of foods and
their storage: avoid using dirty utensils and dishes previously used for cooking and/or
preparing broad beans, store the beans in cupboards in special containers that prevent
contact with other foods, check the labels of ready-made foods, and in the case of meals in
a restaurant, communicate the condition to warn of the need for precaution.
Author Contributions: A.B. and M.M. conceived this review. A.B., M.M. and H.C. authors per-
formed the database research. All authors drafted the manuscript. All authors contributed to the
interpretation of data and critical revision. All authors have read and agreed to the published version
of the manuscript.
Funding: This work was supported by the Current Research funding scheme of the Italian Ministry
of Health.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement: Not applicable.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
World Health Organization. Technical Consultation to Review the Classification of Glucose-6-Phosphate Dehydrogenase (G6PD).
Available online: https://cdn.who.int/media/docs/default-source/malaria/mpac-documentation/mpag-mar2022-session2
-technical-consultation-g6pd-classification.pdf?sfvrsn=1f36be5e_7&download=true (accessed on 18 July 2022).
2.
Salvati, A.M.; Maffi, D.; Caprari, P.; Pasquino, M.T.; Caforio, M.P.; Tarzia, A. Defict di glucosio-6-fosfato deidrogenasi ed anemia
emolitica ereditaria. Ann. Ist. Super. Sanità 1999, 35, 193–203.
3.
Luzzatto, L.; Nannelli, C.; Notaro, R. Glucose-6-Phosphate Dehydrogenase Deficiency. Hematol. Oncol. Clin. 2016, 30, 373–393.
[CrossRef] [PubMed]
4.
Chevion, M.; Navok, T.; Glaser, G.; Mager, J. The chemistry of favism-inducing compounds. The properties of isouramil and
divicine and their reaction with glutathione. Eur. J. Biochem. 1982, 127, 405–409. [CrossRef] [PubMed]
5.
Arese, P.; de Flora, A. Pathophysiology of hemolysis in glucose 6-phosphate dehydrogenase deficiency. Semin. Hematol.
1990, 27, 1–40. [PubMed]
6.
Luzzatto, L.; Poggi, V. Glucose-6-phosphate dehydrogenase deficiency. Nathan Oski’s Hematol. Infancy Child. 2009, 7, 883–907.
7.
Cahill, K.M.; Ley, A.B. Favism and thalassemia minor in a pregnant woman. JAMA 1962, 180, 119–121. [CrossRef]
8.
Mentzer, W.C.; Collier, E. Hydrops fetalis associated with erythrocyte G-6-PD deficiency and maternal ingestion of fava beans
and ascorbic acid. J. Pediatr. 1975, 86, 565–567. [CrossRef]
9.
Corchia, C.; Balata, A.; Meloni, G.F.; Meloni, T. Favism in a female newborn infant whose mother ingested fava beans before
delivery. J. Pediatr. 1995, 127, 807–808. [CrossRef]
10.
Casper, J.; Shulman, J. Bilateral cortical necrosis of the kidneys in an infant with favism. Am. J. Clin. Pathol. 1956, 26, 42–47.
[CrossRef]
11.
Emanuel, B.; Schoenfeld, A. Favism in a nursing infant. J. Pediatr. 1961, 58, 263–266.
12.
Taj-Eldin, S. Favism in breast-fed infants. Arch. Dis. Child. 1971, 46, 121–123. [CrossRef]
13.
Wharton, H.J.; Duesselmann, W. Favism: A short review and report of a case. N. Engl. J. Med. 1947, 236, 74–77. [CrossRef]
14.
Rosen, A.P.; Scanlan, J.J. Favism. N. Engl. J. Med. 1948, 239, 367. [CrossRef] [PubMed]
Nutrients 2023, 15, 343
19 of 19
15.
Pickering, D.E.; Hurwitz, S. Favism in childhood: A case report. Yale J. Biol. Med. 1951, 24, 5–8. [PubMed]
16.
Larkin, V.D. Favism: Report of a case and brief review of the literature. J. Pediatr. 1953, 42, 453–456. [CrossRef]
17.
Tolmas, H.C. Favism: Case report showing heredofamilial tendency. J. Pediatr. 1957, 51, 445–447. [CrossRef]
18.
Diggle, J.H. Favism in London. Arch. Dis. Child. 1953, 28, 369–371. [CrossRef] [PubMed]
19.
McCarthy, O.R. A case of favism. Lancet 1955, 268, 748–749. [CrossRef]
20.
Brooks, E.A.; James, G.A.; Stubber, L.A. Favism in Western Australia. Med. J. Aust. 1958, 2, 455–458. [CrossRef]
21.
Gower, N.D.; Frommer, E. Favism in a Cypriot child. Lancet 1960, 1, 628–629.
22.
Discombe, G.; Mestitz, W. Favism in an English-born child. Br. Med. J. 1956, 1, 1023. [CrossRef]
23.
Choremis, C.; Joannides, T.; Kyruakides, B. Severe opthalmologic complications following favism.
Br.
J. Ophthalmol.
1960, 44, 353–356. [CrossRef]
24.
Stewart, A.G.; Koenigsloew, E.V.; Pabst, H. Favism in a 4-year-old boy. Can. Med. Assoc. J. 1966, 94, 292–294. [PubMed]
25.
Wong, W.Y.; Powars, D.; Williams, W.D. ‘Yewdow’—Induced anemia. West J. Med. 1989, 151, 459–460. [PubMed]
26.
Galiano, S.; Gaetani, G.F.; Barabino, A.; Cottafava, F.; Zeitlin, H.; Town, M.; Luzzatto, L. Favism in the African type of glucose-6-
phosphate dehydrogenase deficiency (A-). BMJ 1990, 300, 236. [CrossRef]
27.
Odièvre, M.H.; Danékova, N.; Mesples, B.; Chemouny, M.; Couque, N.; Parez, N.; Ducrocq, R.; Elion, J. Unsuspected glucose-6-
phosphate dehydrogenase deficiency presenting as symptomatic methemoglobinemia with severe hemolysis after fava bean
ingestion in a 6-year-old boy. Int. J. Hematol. 2011, 93, 664–666. [CrossRef]
28.
Leunbach, T.L.; Pedersen, J.F.; Trydal, T.; Thorgaard, P.; Helgestad, P.; Rosthøj, S. Acute favism: Methemoglobinemia may cause
cyanosis and low pulse oximetry readings. Pediatr. Hematol. Oncol. 2014, 31, 104–106. [CrossRef]
29.
Mohamed, M.; Els, I. Favism in a 15-month-old baby. Blood 2013, 122, 2933. [CrossRef]
30.
Verdugo, L.P.; Calvanese, T.M.; Rodríguez, V.D.; Cárcamo, C.C. Deficiencia de glucosa 6 fosfato deshidrogenasa en niños: Caso
clínico [Glucose-6-phosphate dehydrogenase deficiency in children: A case report]. Rev. Chil. Pediatr. 2014, 85, 74–79. [CrossRef]
31.
Zuccotti, G.V.; Redaelli, F.; Gualdi, V.; Rizzi, V.; Mameli, C.; Dillio, D.; Fabiano, V. Hemolytic crisis in a G6PD-deficient infant after
ingestion of pumpkin. Ital. J. Pediatr. 2014, 40, 1–3. [CrossRef]
32.
Wadowski, B.; Chang, D.; Khan, S.Q.; Chadha, T. Sometimes, It’s Just Black and White: Dark Urine and Pallor in a 2-Year-Old Boy.
Hosp. Pediatr. 2016, 6, 560–565. [CrossRef] [PubMed]
33.
Mansoor, S. Two cases of favism in Israel. Br. Med. J. 1955, 1, 149–150. [CrossRef] [PubMed]
34.
Holt, J.M.; Sladden, R.A. Favism in England—Two more cases. Arch. Dis. Child. 1965, 40, 271–273. [CrossRef] [PubMed]
35.
Oliveira, S.; Pinheiro, S.; Gomes, P.; Horta, A.B.; Castro, A.S. Favismo [Favism]. Acta Med. Port. 2000, 13, 237–240. [PubMed]
36.
Lau, H.K.; Li, C.H.; Lee, A.C. Acute massive haemolysis in children with glucose-6-phosphate dehydrogenase deficiency. Hong
Kong Med. J. 2006, 12, 149–151. [PubMed]
37.
Stockley, R.; Dawson, A.; Slade, R. Favism in two British women. Lancet 1985, 2, 1013. [CrossRef] [PubMed]
38.
Hasler, J.; Lee, S. Acute hemolytic anemia after ingestion of fava beans. Am. J. Emerg. Med. 1993, 11, 560–561. [CrossRef]
39.
Hampl, J.S.; Holland, K.A.; Marple, J.T.; Hutchins, M.R.; Brockman, K.K. Acute hemolysis related to consumption of fava beans:
A case study and medical nutrition therapy approach. J. Am. Diet. Assoc. 1997, 97, 182–183. [CrossRef]
40.
Lim, F.; Vulliamy, T.; Abdalla, S.H. An Ashkenazi Jewish woman presenting with favism. J. Clin. Pathol. 2005, 58, 317–319.
[CrossRef]
41.
Soyuncu, S.; Bektas, F.; Isik, S.; Yigit, O. An unusual syncope cause in the ED: Favism. Hum. Exp. Toxicol. 2011, 30, 335–337.
[CrossRef] [PubMed]
42.
Ata, F.; Javed, S.; Muthanna, B.; Dakhlia, I.; Bint I Bilal, A.; Musa, M.; Uddin, M.; Yassin, M.A. Favism-induced methemoglobinemia
in a G6PD deficient male with a subsequent hemolytic cascade, a therapeutic challenge: Case report and review of literature. Clin.
Case Rep. 2021, 9, 2048–2052. [CrossRef]
43.
Al-Dubai, H.; Al-Mashdali, A.; Hailan, Y. Acute hemolysis and methemoglobinemia secondary to fava beans ingestion in a
patient with G6PD deficiency: A case report of a rare co-occurrence. Medicine 2021, 100, e27904. [CrossRef]
44.
Hartigan, J.D.; Gurnett, T.J. Favism—Report of a case. JAMA 1959, 171, 299–300. [CrossRef]
45.
Torres, C.D.; Chandía, C.M. Insuficiencia renal aguda secundaria como manifestación inicial de favismo en un adulto mayor:
Caso clínico [Favism presenting as an acute renal failure: Report of one case]. Rev. Med. Chile 2012, 140, 1043–1045. [CrossRef]
46.
WHO Working Group. Glucose-6-phosphate dehydrogenase deficiency. Bull. World Health Organ. 1989, 67, 601–611.
47.
Newborn Screening Reference Center-Frequently Asked Questions on G6PD Deficiency. Available online: https://www.
newbornscreening.ph/index.php?option=com_content&view=article&id=75:frequently-asked-questions-on-g6pd-deficiency-
&catid=48:g6pd (accessed on 18 July 2022).
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual
author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to
people or property resulting from any ideas, methods, instructions or products referred to in the content.